All aboard the hype train! There's some spoilers regarding the mission where you rescue Kaz, but it shouldn't be anything major.

• Magazine opens with the editor stating "when MGS V launches on 1 September, I fully expect it to instantly become the best game on PS4". Played the game for 2 days, doesn't explicitly mention how much progress he made.
• The Phantom Pain's prologue is "a real game-changer". Hospital section we've all seen in previews is about an hour long, reminiscent of CoD4's All Ghillied Up. "Kojima's direction and unflinching commitment to challenging expectations and conventions make it the most tense experience ever hosted on PlayStation." Says essays should be written about it. "The cutscene-heavy opening stands apart from the rest of the game - it neither looks nor plays like any of the following 13 hours [...] and could very well go down as Kojima's finest directional hour from any Metal Gear, bar none. Try your hardest not to spoil the madness for yourself."
• Four buddies mentioned: D-Walker, D-Horse, D-Dog, and Quiet. D-Walker is the mech we've seen in some trailers and MGO. Also referred to as a Walker Gear. Not classified as a vehicle. Has a large tech tree, including high voltage stun guns and "robo-CQC". D-Horse, or Diamond Horse, is the starting buddy we've already seen - she can't die, apparently. Diamond Dog Fulton'd from Mission 3 and can spot nearby items and add them to the iDroid map. Quiet is optional, as we know, but "Her presence will lower morale on Mother Base, so you'll have to visit your HQ plenty to pep up the troops".
• Extraction chopper is called Pequod, reference to Moby Dick. "Far from the only reference". A couple of other characters are also named after those in the book.
• Snake has 108 foreign bodies lodged in his body, including shrapnel, bone, and teeth. "It was too risky to remove shrapnel jammed in his brain and heart [...] and according to one of the early cassette tapes, blows to the head could cause him to hallucinate."
• Snake can rescue animals for "effectively a floating zoo", and those too small to be Fulton'd will see Snake shove them in his pockets.
• Using the iDroid, you can send an attack helicopter to distract enemies while you make a getaway. "Wait, did I forget to mention that throughout all this my support helo's pumping out A-ha at full volume? Because it totally is." Plenty of cassette tapes featuring '80s classics can be found inside ghetto blasters and guard outposts.
• Can be played like classic Metal Gear, or however you want - a true sandbox.
• Three locations mentioned: North of Kabul in Afghanistan, the Angola-Zaire Border Region, and Mother Base near the Seychelles.
• 14 or so major bases in Afghanistan (power plants, barracks, towns, etc.), plus over two dozen smaller forts, outposts, and more. No one single base is as big as GZ's Camp Omega, but each location is a unique, hand-crafted area with multiple options for infiltration and exfiltration.
• First mission is to rescue Kaz from town of Da Ghwandai Khar, but first must get intel revealing his exact whereabouts from the village of Da Wialo Kallai. Perfect introduction to game's mechanics. "During missions, The Phantom Pain imposes boundaries on the game world. Should you move past these boundaries you'll be warned that you're leaving the mission area." Can clear out heavily-defended areas by attacking lightly-defended ones and getting them to call for reinforcements from the heavily-defended area.
• SPOILERS: When you reach the extraction point with Kaz, the area fills with gas and the helicopter relocates to a different LZ. The Skulls parasite unit arrive (the magazine compares them somewhat to MGS4's FROGS) - "an 'unkillable' squad of zombie-esque supersoldiers with glowing green eyes, capable of outrunning D-Horse at full speed."
• Their arrival isn't a surprise at all, because the mission's opening credits revealed them; missions are called Episodes, complete with opening producer, designer, creator, and writer credits, as well as a who's who of that episode's stars.
• After a close pursuit, the mission ends, and the player finds they have only completed two of six objectives; every episode has hidden sub-objectives that are only revealed after completing it at least once (to encourage replaying), and can unlock bonus blueprints and cassette tapes. Specifically, he got (1) Find Kaz, and (2) Save Kaz, but didn't know to extract a couple of other characters, stealth past the final baddies, and uncover a stash of rough diamonds.
• Certain sub-objectives can only be completed with the better kit that you get later in the game.
• Mission structure is linear but open: Episodes 3, 4, and 5 all unlock at the same time. One involves killing a Spetsnaz special forces soldier, another features an assault on a communications relay to cut radio chatter between outposts and isolate troops, and another is a rescue mission for a captured engineer.
• Completing any two of those will open Episode 6, "a story-driven, critical-path objective".
• Snake needs to extract translators available in certain Side-Ops to understand soldiers during interrogations. The player tried to extract a mortar to HQ, but hadn't upgraded the Fulton enough, so it fell and made "an almighty clank", causing a distraction that ultimately helped extract the translator while the others went to investigate.
• Player expects a lot of side ops available in the final game, judging by the numbering (Pooyan better return or riot). Can involve capturing translators, eliminating certain targets, recruiting skilled soldiers, "rescuing crazy survivors from Mother Base's destruction nine years ago", and tranq'ing a legendary brown bear and Fultoning it back to HQ.
• 'Important' side ops can trigger a surprise story episode when you least expect it.
• "The marathon cutscenes for which Kojima's most famous? Hold onto something: they've almost gone. There are some cutscenes, yes, but don't expect to be able to settle down with a bucket of popcorn and give the pad a rest for an hour or two at a time. [...] key missions will bring some plot, but really the vast majority of The Phantom Pain's exposition lives in the cassette tapes you unlock after every major story beat, which contain plenty of information about past events and unseen goings-on at Mother Base."
• Pre-mission deployment (only available from Mother Base?) opens up with you choosing a loadout: two primary weapons, one secondary, bionic arm type, tools (grenades, C4, etc.), items (cardboard boxes, Phantom Cigar, etc.), vehicle, deployment time, buddy, and playable character (similar to Peace Walker, you can play as soldiers, like Dire Crocodile or Growling Eel).
• Mother Base "is where The Serious Business™ takes place".
• Mother Base management is mentioned - sounds pretty much like Peace Walker. The base itself doesn't have a visitable interior ("the closest thing to an indoors area is a small open-air brig"), but they do admit their Mother Base was only a fraction complete after two days of building.
• Mother Base's online base assaults, akin to Dark Souls invasions, can be switched off in the menu if you don't care for it. Takes place on separate Forward Operating Base. Gives you a chance to use weapons you may not otherwise use if you play the game stealthily and non-lethally. Invaders get the chance to steal weapons and equipment they haven't otherwise yet unlocked.
• "It's a lot to absorb, and the terrifying truth is there's a lot more that I sampled in my two-day marathon session that I'm not yet allowed to discuss."
• Moments of near-photorealism. Skies are "gorgeous".
• "The wait for September is going to be excruciating, but when MGS V finally arrives it's going to be so much more than anybody but Kojima himself had envisioned."

There's some other info from the 16 page preview, but most of it has already been said (no new info for MGO, for example), or recounts personal experience on some missions and is tough to get across without literally writing it all out. These are all the new things that have got me more hyped, though. Sorry that I have no pics/scans.